The proposed work is a continuation of the development of "phospholipid" renin inhibitors as pharmacologic tools to explore physiologic and pathophysiologic mechanisms of experimental hypertension and determination of the clinical potential of this class of agents as therapeutic and/or diagnostic antihypertensive drugs. The objectives are based on the finding that, in the acute and chronic two and chronic one kidney Goldblatt hypertensive rats, and in the SHR rat eicosatetraenyl (3-aminopropyl) phosphonate (URI-73A) has been demonstrated to lower blood pressure and the activity of renin, the enzyme component of the renin-angiotensin system. The chemical synthesis of quantities of URI-73A and structurally related analogs sufficient for dose information, pharmacological and biological studies, is proposed.